West Nile Virus Death Toll Climbing October 11, 2012

The number of humans with West Nile Virus climbed 40% this week, bringing the total to 4,249 cases and 168 deaths. All contiguous states have reported cases and are on alert to take preventive measures as the CDC warns that more deaths are expected.

West Nile Virus comes to us through infected birds via mosquitos and is worst during summer months, tapering off in fall. A small number of dogs and cats have been infected, and some hundreds of horses. Many horse owners have opted for the equine vaccine, however, no vaccine exists for humans. There have been no cases of horses transmitting the virus to other horses or to humans. The only human transmission of the disease was transplacental, reported in 2002, and one case of transference through breast milk.

Symptoms and Risk Factors

Symptoms appear between 3 and 14 days after being bitten by an infected mosquito. Approximately 80% of infected people will show no symptoms. About 20% present with fever, headache, body aches, nausea, vomiting, swollen lymph glands and occasionally a skin rash on chest, stomach and back. One in 150 infected will develop severe neuroinvasive disease such as West Nile encephalitis, West Nile meningitis, West Nile meningoencephalitis and West Nile poliomyelitis, and require hospitalization. However, to date 53% of reported cases have been classified as neuroinvasive. Symptoms of severe disease can include high fever, neck stiffness, disorientation, coma, tremors, convulsions and paralysis. In all cases the symptoms may last several days or several weeks.

Residents of any area where virus activity has been identified are at risk. People over age 50 are of highest risk.

Prevention

Mosquitos breed and lay their eggs in shallow, standing water. Several times per week empty water from pet dishes, birdbaths, buckets and cans. Clean out any clogged rain gutters. Drill holes in tire swings to allow water to drain.

Communities and cities may use vector management programs to reduce mosquito populations.

Try to remain indoors during dawn and dusk when mosquitos are most active. Wear protective clothing and then spray the clothing with an insect repellant containing DEET.

Ensure all doors and windows are screened, and consider using mosquito netting around cribs and children’s beds in areas with highest rates of West Nile Virus.

Do not handle dead birds. Contact your local health department to dispose of the body.